This invention relates to improving processing characteristics with aromatic sulfide polymers. In one of its aspects this invention relates to affecting the curing rates of arylene sulfide polymer mixtures. In another of its aspects this invention relates to the classification of arylene sulfide polymer mixtures by particle size. In still another of its aspects this invention relates to the separation and blending of portions of arylene sulfide polymer mixtures that have been classified by size.
In the processing of commercially produced arylene sulfide polymer a problem can occur, particularly when using fiber grade mixtures in that curing during pelletizing or spinning results in detrimental screen pack blinding. It has now been found that there is a gradient in the rate of cure depending upon the size of polymer particle in commercially produced arylene sulfide polymer such that by suitable size exclusion methods particles within certain size ranges of a mixture can be segregated, excluded from the mixture, or reblended with another mixture to provide blends or mixtures having cure rates within the most desirable ranges for certain applications, i.e., relatively lower cure rates for fiber operations or relatively higher cure rates for molding or coating polymer blends.
It is therefore an object of this invention to provide a method for adjusting the cure rate of a mixture of arylene sulfide polymer particles. It is a further object of this invention to provide a method for producing mixtures of arylene sulfide polymer having relatively high or relatively low cure rates as compared to as-produced polymer mixtures. It is another object of this invention to provide mixtures of arylene sulfide polymers having adjusted cure rates. It is still another object of this invention to provide fibers, molded objects, polymeric coatings, and film and plate extrusions of arylene sulfide polymers having adjusted cure rates.
Other aspects, objects and the various advantages of this invention will become apparent to those skilled in the art upon reading this specification and the appended claims.